Light emitting diode (LED) has become a new-generation light source for illumination due to its advantages such as power saving and long lifespan, and the LED is used extensively as a light source in many different fields and it gradually replaces traditional incandescent lamps and fluorescent tubes. For example, a long striped substrate including a plurality of high-brightness light-emitting diodes (HB-LED) arranged in a row is used to replace the fluorescent tube. However, the intensity of the illumination of the LED is relatively low and the illumination is not uniform enough, such that its application as a lamp still requires a lamp shade to perform a secondary light distribution. However, most LED lamp shades available in the market and used for the secondary light distribution emphasize on the protection of the light source only, but such conventional LED lamp shades usually provide no design for a more efficient light distribution of the LED light source. Even though some LED lamp shades may come with an anti-glare design or a simple secondary light distribution design, a common design with a spherical surface generally results in a less efficient light distribution effect.
In addition, the lamp shade used for the traditional light source (incandescent lamp or fluorescent tube) emphasizes on the protection and decoration of the lamp only, but seldom provides a functional effect or improves the light distribution of the light source. The design of some lamp shades may take the light distribution of the lamp shade into consideration, but the conventional lamp shade only comes with a simple light distribution design, such as using a cylindrical surface as the curved surface of the lamp shade, and such cylindrical surface has no or little change of curvature that can just proportionally narrow the light emitted from the traditional light source, but such lamp shade cannot be applied to the lamp of the LED light source at all. More specifically, the LED light source is close to a point light source whose emitting light has the greatest brightness at the middle and a decremented brightness towards the periphery, so that when the lamp shade for the traditional light source is applied to a lamp of the LED light source, the LED light source will be further narrowed proportionally, and thus resulting in a phenomenon of a too-bright middle (or a non-uniform light illumination). Particularly in most of the present existing lamps applied for the planar illumination, the too-bright middle phenomenon will be more significant. To improve this problem, related designers and manufacturers adopt a solution of installing more LEDs, but such design of installing more LEDs further introduces the drawbacks of high power consumption and incompliance with the cost-effectiveness and the power saving effect of the LED lamps.
Therefore, it is a main subject of the present invention to disclose a lamp shade of an LED light source that provides a functional effect or improves the light distribution of the light source to overcome the aforementioned problems of the conventional lamp shade having a poor light distribution.